화성에서 발견된 고대 바다의 흔적 – 이것은 ‘생명의 가능성이 더 높다’는 것을 의미합니다.

28개의 이미지에서 수집한 이 사진은 탐사선이 “Greenhue Pied”라고 불리는 지질학적 특징의 가파른 경사를 오른 후 NASA의 큐리오시티 마스 우주선에서 찍은 것입니다. 이미지 위의 거리에는 연구원들이 한때 거대한 바다였다고 믿는 Aeolis Dorsa라고 불리는 지역 근처에 있는 Gale Crater의 바닥이 있습니다. 크레딧: NASA/JPL-Caltech/MSSS

고대 북극해에 대한 새로운 증거[{” attribute=””>Mars has been uncovered in a recently released set of topography maps. These maps offer the strongest case yet that the planet once experienced sea-level rise consistent with an extended warm and wet climate, which was far different than the harsh, frozen landscape that exists today.

“What immediately comes to mind as one the most significant points here is that the existence of an ocean of this size means a higher potential for life,” said Benjamin Cardenas, assistant professor of geosciences at Penn State and lead author on the study recently published in the Journal of Geophysical Research: Planets. “It also tells us about the ancient climate and its evolution. Based on these findings, we know there had to have been a period when it was warm enough and the atmosphere was thick enough to support this much liquid water at one time.”

Whether Mars had an ocean in its low-elevation northern hemisphere has long been debated in the scientific community, Cardenas explained. Using topography data, the research team was able to show definitive evidence of a roughly 3.5-billion-year-old shoreline with substantial sedimentary accumulation, at least 900 meters (3,000 feet) thick, that covered hundreds of thousands of square kilometers.

최근에 발표된 지형도 세트는 화성에 고대 북부 바다가 있었다는 새로운 증거를 제공합니다. Penn State의 지구과학 부교수인 Benjamin Cardenas는 이 지도가 오늘날 존재하는 혹독하고 혹독한 풍경이 아니라 장기간의 따뜻하고 습한 기후와 일치하는 해수면 상승을 본 적이 있다는 가장 강력한 증거라고 말합니다. 크레딧: 펜실베니아

Cardenas는 “이 논문에서 우리가 수행한 크고 새로운 일은 지층과 퇴적 기록의 관점에서 화성에 대해 생각하는 것입니다.”라고 말했습니다. “지구에서 우리는 시간이 지남에 따라 퇴적된 퇴적물을 관찰하여 수로의 역사를 플로팅합니다. 우리는 그 층을 물이 퇴적물을 운반한다는 생각이라고 부릅니다. 퇴적물이 쌓이는 방식을 이해함으로써 지구의 변화를 측정할 수 있습니다. 그것이 바로 우리가’ 여기서 했어 – 하지만 화성이야” .

연구팀은 미국 지질조사국(US Geological Survey)에서 개발한 소프트웨어를 사용하여 미국 항공우주국(National Aeronautics and Space Administration)의 데이터로 지도를 만들었습니다.[{” attribute=””>NASA) and the Mars Orbiter Laser Altimeter. They discovered over 6,500 kilometers (4,000 miles) of fluvial ridges and grouped them into 20 systems to show that the ridges are likely eroded river deltas or submarine-channel belts, the remnants of an ancient Martian shoreline.

Elements of rock formations, such as ridge-system thicknesses, elevations, locations, and possible sedimentary flow directions helped the team understand the evolution of the region’s paleogeography. Now known as Aeolis Dorsa, the area that was once ocean contains the densest collection of fluvial ridges on the planet, Cardenas explained.

There has long been debate in the scientific community about whether Mars had an ocean in its low-elevation northern hemisphere. Using topography data, a Penn State led research team was able to show definitive evidence of a roughly 3.5-billion-year-old shoreline with substantial sedimentary accumulation, at least 900 meters thick, that covered hundreds of thousands of square kilometers. Credit: Benjamin Cardenas / Penn State

“The rocks in Aeolis Dorsa capture some fascinating information about what the ocean was like,” he said. “It was dynamic. The sea level rose significantly. Rocks were being deposited along its basins at a fast rate. There was a lot of change happening here.”

On Earth, the ancient sedimentary basins contain the stratigraphic records of evolving climate and life, explained Cardenas. If researchers want to locate a record of life on Mars, an ocean as big as the one that once covered Aeolis Dorsa would be the most logical place to start.

“A major goal for the Mars Curiosity rover missions is to look for signs of life,” Cardenas said. “It’s always been looking for water, for traces of habitable life. This is the biggest one yet. It’s a giant body of water, fed by sediments coming from the highlands, presumably carrying nutrients. If there were tides on ancient Mars, they would have been here, gently bringing in and out water. This is exactly the type of place where ancient Martian life could have evolved.”

Cardenas and his colleagues have mapped what they have determined are other ancient waterways on Mars. An upcoming study in the Journal of Sedimentary Research shows various outcrops visited by the Curiosity rover were likely sedimentary strata from ancient river bars. Another paper published in Nature Geoscience applies an acoustic imaging technique used to view stratigraphy beneath the Gulf of Mexico’s seafloor to a model of Mars-like basin erosion. The researchers determined that fluvial ridges, landforms found widely across Mars, are likely ancient river deposits eroded from large basins similar to Aeolis Dorsa.

“The stratigraphy that we’re interpreting here is quite similar to stratigraphy on Earth,” Cardenas said. “Yes, it sounds like a big claim to say we’ve discovered records of large waterways on Mars, but in reality, this is relatively mundane stratigraphy. It’s textbook geology once you recognize it for what it is. The interesting part, of course, is it’s on Mars.”

Reference: “Paleogeographic Reconstructions of an Ocean Margin on Mars Based on Deltaic Sedimentology at Aeolis Dorsa” by Benjamin T. Cardenas and Michael P. Lamb, 12 October 2022, Journal of Geophysical Research: Planets.
DOI: 10.1029/2022JE007390

The other coauthor on the JGR: Planets paper is Michael P. Lamb, professor of geology at Caltech. The work was funded by the National Aeronautics and Space Administration (NASA).